Japan's Cosmo Oil Company said it has given up on commercial production from the Block 11 offshore oil field in Opec producer Qatar and has booked a 3.5 billion yen ($43 million) special loss as a result.

Cosmo, Japan's fourth-biggest oil refiner, said it and its partners could not find enough oil reserves in the block after they had drilled two trial wells.

Cosmo's wholly owned subsidiary, Cosmo Energy Exploration & Development Ltd, acquired a 29.5 percent stake in the field in 2008. Its partners were Germany's Wintershall Holding, the operator, and Anadarko Qatar Block 11 Company.-Reuters